New alleles of the HLA-B15 family.

In a previous study of B locus alleles by sequence-specific oligonucleotide probe (SSOP) hybridization, we observed 18 novel patterns in a panel of 360 individuals. Four of these novel patterns were caused by alleles of the human leukocyte antigen (HLA)-B15 group, and three were available for this study. These alleles were found in Oriental, Latin American, African American, and Caucasian individuals. In addition, we analyzed a Caucasian subject who was found by serology to have an unusual B15 specificity. We sequenced these four samples by performing amplification from genomic DNA using polymerase chain reaction primers designed to obtain HLA class I products that included exon 2 and exon 3 as well as the intervening intron. The amplified segments were cloned and identified by colony hybridization with nonradioactive SSOP. Nucleotide sequences were obtained using an automated DNA sequencer. The allele B*1530 differs from B*1501 by a substitution of Asp for Asn in position 114 and Ser for Tyr in codon 116. The new allele B*1531 differs from B*1502 at amino acids 94, 95, and 152. The variant B*1524 was found to have N-77, I-80, A-81, L-82, R-83. A similar motif exists in B locus alleles that have the supertypic specificity Bw4 and in B*1513, B*1516, B*1517, and B*1523; it is likely to have been generated by gene conversion. Finally, the novel allele B*1527 is similar to B*1501 except for the presence of Phe instead of Tyr at position 99. Because this change exists also in B*1506, it is possible that B*1506 was derived from B*1501 through B*1527. It is of interest that a similar substitution (Cys for Tyr at position 99) distinguishes A*0201 from A*0207 and is known to determine an epitope recognized by T cells. Thus, B*1527 may also carry a change that is functionally relevant in cell-mediated immunity.